stiokney



" (No Model.) 2 sheets-sneer 1.

O. W. STI-GKNEY.

, PROCESS OF ROASTING ORES.

Patented May 31, 1892.

ll'lnwwesl W 1. imam 31 I Zia man (No Model.) 2 Sheets-Sheet 2. 0. W.STIOKNEY.

PROCESS OF ROASTIING 0113s. No. 475,824. Patented May 31, 1892.

PATENT Orricn.

CHARLES WADE STICKNEY, or BUTTE orrv, MoN'rAnA.

Pact-zen eeao'Asriuo-ones.

SPECIFICATION forming part of Letters Patent No. 475,824, dated May 31,1892. Application filed December 29, 1890. Serial No. 376,185. (Nospecimens.)

To all whom it may concern.-

Be it known that 1, CHARLES W ADE STICK- NEY, a citizen of the UnitedStates, residing at Butte City, Montana, have invented a certain new andimproved Process for Roasting I am aware that ore has been roasted by.

steam, andalso bysteam and air combined, and

that superheaters have been used for this pur-' pose. The ditiiculty andimpracticability of such processes have been that the superheaters weremade of metal, and while they would worlr at temperatures below a redheat and either convert the ores into sulphates or mechanically carryoff a large part of the sulphur they cannot economically roast the oresto such a low per cent. of sulphur as to fit them for smelting for thebase metals for the reason that when the sulphur has been reduced tobelow fifteen per cent. the ore is so, reduced in heat that the steam isnot fully decomposed, and in consequence alarge partof the ore escapescomplete desulphurination unless the'steam be made red-hot beforeentering the ore. Superheaters of metal at a red heatthemselvesdecompose the steam and rapidly oxidize. l have obviated this diffieultyby the material and peculiar construction of niysuperheater, using anoutside metal casing or frame to resist pressure and a nonmetallicnon-onidizab1e refractory lining, and exposing a very largeintenselyhe'ated surface in the interior.

l am also aware that ore has been roasted by steam and air in suchmanner as to produce snlphureted hydrogen and sulphurousacid gas in suchproportions that they will unite and drop their sulphur when brei'ightinto contact with water where the sole object to the sulphur. Theditliculty of using this process for smelting purposes is that it cannotroast close enough without using a separate superheater, which canmaintain the steam at red heat independent of the temperature of theore, and also that the sulphur so formed is in the form of a powder soimpalpable as to form a sort of milk from which thesulphur will notsettle in any reasonable time, making the process impracticable wherethere is but little water and no water-shed which can be used to run offthe milk without being a nuisance to thousands of people. To obviatethis difficulty, I make use of the action of sulphate of alumina forcausing the sulphurto aggregatein coarse particles and readily settle,leaving the water clear to be used over again without loss of orchemical action upon the salt.

In the drawings, Figure 1, A shows a steamgenerator; B, the superheater,having a'heating-chamber 'z'. m shows the steam and air duct leading tothe ore-furnace O. z is the gas-escape pipe. 3 t are pipes forming theatomizer. 'u, is the tank for solution of salts. D is thecooling-boiler. F is the connectingpipe, leading gas from an ordinarySpence air-roasting furnace. (Shown in Fig. 2.

Fig. 3 shows across-section of the air and steam duct m.

The construction is as follows: The steamgenerator is an upright boiler,through the fines of which the smoke and Waste heat from the superheaterB are made to pass by the flue a. From this boiler a pipe 1), controlledby a valve 0, conveys the steam to the superheater. Into the pipe 1)leads a piped from an air-blast controlled by a cock 2, and from thepipe d branches off a pipef, with a control-valve, which leads directlyto the tuyeres of the ore-furnace.

B is the superheater. Both material and construction of this areimportant. It must be of nonmetallic refractory non-onidizable materialand heavily ironed externally, easily charged with coal or coke, andenposealarge heated surface internally. I prefer to make it ofboileriron and lineit with fire-elaybriclrs and fire-clay mortar. It hasa grate g and an ash-pit below. Above the grate it has iron girders,which support several pipes made of fire-clay h 71, like. These pipesstand on end and extend to near the top oi" sheater. 'The interiors termtines for the tire the enteriors form the lieatinghrface of thesuperheating-chamber 2'. These pipes are molded with square tops orcollars and similar bottoms, so that when stood up together the tops andbottoms form ceiling and floor of the heating-chamber, which are thencovered with a layer of fire-clay. The Hues may have an iron pipe forinside lining.' A top piece covers the ceiling, (except the-fiue-holes)which i is bolted tothe base by long rods. The top of the superheater isa brickarch; At the apex isset a hopper 3', closed with an invertedconical pan K, made of boiler-iron, closing the aperture tight after thecoal islet in. The coal dumped into the hopper j is allowed to fallthrough the flues into the fire-box. The heatin g-chamber 2' has nocommunication with the fire-box or fines. From the heatingchamher 'i aniron flue lined with fire-brick leads around the base of the ore-furnaceC, which is an ordinary waterjacketed furnace having an arched top offire-brick surmounted by a hopper and cone-stopper 1 similar to those onthe top of the snperheater. Thisis the means for charging the furnacewith ore. The steam-tuyeres X are upon one side'of the furnace and theair-tuyeres on the other side.

The object of the split in the blast-pipe is this: When the ore in thefurnace contains a great dealof sulphur, the air is advantageouslyturned in cold; but when the bulk of the sulphur is eliminated and theore becomes too cold to decompose the steam the air-may then be turnedin through the snperheater.

In the latter case a damper y inthe base-duct 'plate, but which can bereadilyopened'and a rod inserted into the furnace for breaking up anycrusts that may form.

Just below the duct m is a door 0 for re moving the roasted ore. In thedoor is a taphole 19. In running some ores it is advantageous to raisethe heat sufficiently to melt the roasted ore and run it out as a matte.The gases, sulphureted hydrogen, and snlphurousacid gas are formed fromthe steam and sulphur, while the air oxidizes the ore, the relativequantities being carefully regulated to produce this result. The gasesescape into a tire-clay duct 2, where they meet with a cloud ofatomized-water holding in solution sulphate of alumina. The manner ofproducing this cloud is to convey a jet of airor steam from theair-blast or boiler into the ductz hya pipes, and unite the latter witha pipe i (preferably nonmetallic) for water, so that the jet blows outof pipe 25 near its end. The other end of pipe I. extends'down into thetank u, which is filled with the solution, which is thus drawn up andatomized in the d not 2. The latter leads down into the tank 11. belowthe water-level. In some cases, however, it is advisable to pass thegases and atomized water through the fines of a boiler D, supplied withcold water, and in case it is not desired to save the sulphur the tankand salts may be omittedand the sulphur blown out through the coolerflues into the air, and subsequently treated mechanically to extractmetallic dust. If the tank and salts are used, the heat of the gasesevaporates the water, keeping up the strength of the solution. Theboiler is used so that heat is saved to return to thehoiler generatingsteam. The latter may then draw a hotwater supply from the boiler D bymeans'of an injector E and the pipe 0, or may draw from the water-jacketof the furnace by a pipe 1;. The temperature of the water-jacket iscontrolled in the usual way with blast-fu rnaces. v

The operation is as follows: Ore is charged into the furnace and coalinto the superheater, a fire having been started in the latter. When thepipes are red-hot and steam up, the steam valve is opened, and enteringthe superheater is raised to or above '1000 Fahrenheit, and thusentering the ore it is decomposed, forming sulphureted hydrogen andsulphurous-aeid gas. Air is then turned in, producing oxides of themetals and more sulphurous-acid gas. Theoretically the reactions are asfollows:

The gases pass out into the duct m, where they meet and mingle with thecloud produced by the atomizer carrying the salts in solntien. Thesulphur precipitates in a ready-settling form and settles in thebottomof the tank and, after some accumulation, is drawn-off at w,washed, and the washings returned to the tank, in order to lose aslittle of the salts as possible. The sulphur is removed from themetallic dust by a simple and rapid methodv 1 of concentration by reasonof its slight specific gravity. The reaction by which it is precipitatedis as follows:

' Practically the smell of the tank is the test for regulating the steamand air. When just right, there is practically no odor a short distanceaway.

Trio not claim, broadly, the process of generating sulphureted hydrogenfrom the ore by means of steam, and znilphurous acid by means of air,and the precipitation of the sulphur by means of water or steam jets,for I am aware that this has been done where the sole objectwas to getthe sulphur, and the residue was worthless for metal; but my'combinationof a superheater for the steam which will bear a red or higher heatwithout being rapidly eaten out makes it possible to deposit the sulphurin solid form, and at the same time leave valuable metal ores in a fitstate for smelting to extract the metallic contents. My method, also, ofcausing the sulphur to rap- IOC idly settle is new in the process ofore-roasting. In my process I use sulphate of alumina, as it gives acheap method of keeping upthe strength of the solution in the atomizedwater and tank, so that it is not necessary to wash the sulphur torecover the salts. I dissolve sulphate of alumina in the tank; butinstead of renewing it I mingle in any convenient way a small stream ofwater with the solution coming out of the atomizer, holding insuspension a clay having a large per cent. of hydrate of alumina. Iregulate theair so that there shall be a slight excess of sulphurousacidgas arriving at the atomizer. The latter, used with an air-blast or airmingled with steam, generates small quantities of sulphuric acid, which,reacting on theelay, forms sulphate of alumina, thus making up the losscaused by some of it adhering to the removed sulphur. The sulphur canthen be removed from the metallic dust by melting, while the metallicdust settles to the bottom. it the sulphur is desired for use, it can beobtained free from clay by distillation.

In case air-roasting furnaces are already built and it is desired todestroy the noxious fumes from these their gas-outlets arejoined withthe gas-exitductof myfurnace, as shown at F. Steam alone is then letinto my furnacc. This causes one-half the sulphur to distill insolid'form,vaporized,-and'the steam to divide between the ore and theremaining sulphur, giving the reaction:

Two tons are roasted in my furnace to dispose of the gas in one ton inordinary airroasters; but this is made easyfrom the great rapidity ofaction of my furnace when working the steam at or above a red heat.

I am aware that superheaters for steam comprising tubes of fire-clayhave been used in the process of making oil and water gas; that ducts ofrefractory material have been used to convey hot gases or vaporto andfrom ore-kilns, and that outer openings have been used in the wind-chestto pigment furnaces; that in the manufacture of coal, oil, and water gaswater-jackets have been used around a furnace and pipes run from thenceto sup ply hot'water to the steam-generator. I do not claim any ofthese, except as above described, in connection with the process ofroasting ores and depositing the sulphur in solid form.

- described.

and depositing the sulphur in solid form, the

following: r

1. The process which consists in generating steam in a boiler, passingit into a chamber maintained at a red orhigher heat, and thence throughsuitable ducts into a separate fur nace containing ore, and conductingthe resulting gases into a cloud of atomized water holding sulphate ofalumina in solution,su bstantially as described. 1

2. The process which consists in generating steam in a boiler, passingit iuto'a chamber maintained at a red or higher heat, and thence throughsuitable ducts into afurnace containing ore, and mingling the resultinggases in contact with a solution ofv sulphate of alumina, substantiallyas described.

3. The process which consists in injecting steam at a red or higher heatinto a furnace containing ore, whereby sulphureted hydrogen isgenerated, roasting another portion of ore by means of air, wherebysulphurous-acid gas is generated, and mingling these gases in contactwith a solution of sulphate of alumina,

whereby the sulphur precipitates in coarse and ready-settlin gparticles, substantially as 4. The process which consists in injectingsteam at a red or higher heat into a furnace containing ore, wherebysulphureted hydrogen is generated, and roasting another portion of etcby means of air, whereby sul phurous-acid gas is generated, and minglingthese gases in contact with-water holding clay in suspension, wherebysulphate of alumina is generated and its solution mingled with thegases, substantially as described.

CHARLES WADE STICKNEY. Witnesses:

G. l. STICKNEY,

W. W. Wnsuou.

